Broadband superior electromagnetic absorption of a discrete-structure microwave coating

• Discrete-structure absorbers were prepared by dividing conventional absorbers.
• Microwave absorbing properties of discrete-structure absorbers were investigated.
• The absorbing properties of absorbers can be improved with the discrete-structure.
• The mechanism of discrete-structure absorbers were discussed.

A method of improving the electromagnetic (EM) absorption property of conventional microwave absorber (CMA) is proposed here. The structural design process was mainly concerned with systematic analysis and research into the impedance matching characteristic and induced current. By processing a CMA-carbonyl-iron powder (CIP) coating into many isolated regions, the discrete-structure microwave absorber (DMA) had a much better absorption property than the corresponding CMA. When the thickness was only 2.0 mm and the component content was 33 wt%, the loss of reflection was less than −10 dB shifted from 6–7 GHz to 7–13 GHz and the loss of minimum reflection decreased from 12.5 dB lost to 32 dB lost through a discrete-structure process. The microwave absorption properties of coatings with different component contents and thicknesses were investigated. The minimum reflection peaks tended to shift towards the lower frequency region as CIP content or coating thickness increased. By adjusting these three factors, a high-performance broadband absorber was produced.